Field of the Invention
The present invention relates to a golf club head.
Description of the Related Art
A wood type, iron type, hybrid type, utility type, and putter type golf club heads or the like are known as a golf club head. A variation in a hit point is inevitably generated in the heads of all the types. A head having high rebound performance at all the hit point positions is preferable.
In a head disclosed in Japanese Patent Application Laid-Open No. 2012-5679 (US2011/0319190), a face part includes a thick part located in a middle, and an outer peripheral part located at an outer periphery of the thick part. The thick part includes a central part having the greatest thickness, a first ridge surrounding the central part, and a first valley located between the central part and the first ridge. An object of the invention of the gazette is to provide a head in which a CT value in a hit point other than a sweet spot is almost equal to a CT value in the sweet spot.
Japanese Patent Application Laid-Open No. 2010-279847 discloses a hollow golf club head including a face part and a head main part. The head main part includes a fold-like part bent in an approximately U-shaped section. The fold-like part forms a groove-like part in an outer surface of the head. The fold-like part extends to a crown part, a side part, and a sole part along a peripheral edge of a face surface. The fold-like part can decrease the rigidity of the whole head to achieve high rebound performance.
Japanese Unexamined Patent Application Publication No. 2013-527008 (US2011/0294599) discloses a hollow head having a stress reduction feature (SRF). The SRF includes a crown side SRF and a sole side SRF.
A head structure intended so that a face part is deflected in a well-balanced manner is disclosed in Japanese Patent Application Laid-Open No. 11-114102. In the head, a tangent of a face surface is S1; a face side tangent of a crown face is S2; a face side tangent of a sole surface is S3; an angle between the tangent S1 and the tangent S2 is α; an angle between the tangent S1 and the tangent S3 is β; and a supplementary angle of the angle β in the tangent S3 is γ. In the head, α and β are almost equal to each other, or α and γ are almost equal to each other.
Japanese Patent Application Laid-Open No. 10-263118 discloses a hollow head including a deformation promoting part. The deformation promoting part increases the deflection of a face part, or increases the relative displacement of the face part to the head. As the deformation promoting part, a thin-walled groove or a penetration groove provided in the face part is disclosed.
U.S. Pat. No. 7,582,024 discloses a head including a main body and a face insert. A slot is provided around the main body near the face insert.
Japanese Patent Application Laid-Open No. 2003-325709 discloses a golf club head in which a plurality of joint pieces connecting a face wall part and a back face wall part to each other, and a void located between the joint pieces are formed.